Vacuum chuck for glass lathes



A, April 23 1946. c. B; PETRY 2,398,959

VACUUM CHUCK FOR GLASS LATHES Filed Sepl'.. 1 0, 1943 mms/rpg? "wrok/virPatented-Apr. 23, 1946 2,398,959 l VACUUM CHUCK non eLAss Lamas aCharles B. Petry, Fair Lawn, N, J.. assignorto Allen B. Du MontLaboratories, Inc., Passaic, N. J., a corporation of DelawareApplication September i0, 1943, Serial No. 501,794

2 Claims.

'lhis invention relates to a device for attaching glass objects tolathes so as to be able to perform work on such objects convenientlywithout requiring mechanical clamps or the like.

with this invention glass objects, such as tubes used for makingosciliographs for example, can be easily and quickly attached to andremoved from a lathe chuck without breaking the glass.

The tubes are securely held in place whilethe lathe is turning and workis being done on the glass by means of blow'torches, etc.

In vcarrying out the invention a chuck isprovided for a lath'ethat has aface against whichl the work is seated and held in place by means of a'vacuum applied through the chuck to keep the work properly located andcause it to turn as the chuck turns.

The invention may be understood from the description in connection withthe accompanying drawing, in which:

a Fig. 1 is a longitudinal section through the device, which is to beattached to the head stock of a lathe: and

Fig. 2 is a modification of one of the parts.

In the drawing, reference character I indicates a plate having a ange 2for convenience in attaching it to"the head stock of a lathe. A shaft lI is provided with a. shoulder 4 and a threaded extension 5 forconnecting it to the center of theplate I. The other end of the shaft 3is provided with a shoulder 6 which carries a thick disc 'I which has adished outer face 8. ,A circular groove l is provided in this faceyand agasket I Il, which may be of rubber or other inafterlal and'may be ofcircular or other shape in cross section, is laid in thisgroove. i

A sylphon bellows 'I2 has portions I3 iitting, in a practicallyair-tight manner, against surfaces Il on the shoulders 4 and l so thatthe shaft'3 can turn without turning the bellows I2. The middle portionofthe bellows I2 is provided with a ring Il having a hole in which oneend o1' tube I. ts. the other end of this tube fitting in the' side ofvacuum chamber Il. The shaft 3 is provided with a conduit Il from anintermediate portion through the disc- I.

The vacuum chamber I'I is provided with a' v nection 22 is pivoted on anextension 24 on the inside of chamber I1 and is normally held open by aspring 25 when a vacuum conditionexists in this chamber. An operatingrod 26 extends from valve 23 to the outside of chamber I1 for 5manipulating this valve.

, The plate I is connected to the head stock of a lathe in anyconvenient way so that it is revolved around a xed axis.

The operation is as follows:

l0 The glass tube upon which work is to be done is placed with 'itsYbottom pressingI against the gasket Ill to close the space within thisgasket, and the valve 23 is opened by pushing rod.26, whereupon thevacuum appearing inside the 15 gasket III- and between the face 8 andbottom of the tube holds the tube in place. After the tube 'has beenprocessed or when it is desired to remove it for any reason, the valve-I9 is opened momentarily by pressing the head and at the face of thedisc 8 lis broken, thus releasing the tube without appreciable effect onthe 'main vacuum source because the rush of air through the pipe 22sucks the valve 23 against 25 the end of pipe 22 thus preventing furtherloss of vacuum. Also, accidental removal of the tube that is beingprocessed or too much leakage of air into the space inside of the gasketII) or breakage of a portion of the tube inside this gasket will permitan inrush'of air to close the valve 23.

In the modification shown in Fig. 2 the corresponding parts are shown bythe same reference characters with primes. In this modification flexiblediscs 28 are hermetically attached to the ends of the ring I5'. Each oneof these rings is a a hub 29 in which the shaft 3' isprovidedl witrevoluble. A compression spring 30 between the discs 28 press the sameoutwardly s'o that the rounded ends of the hubs 29 bear against'the endsoii to make better provision against leakage.

What is claimed is: 1. In a device of the character described, a

'45 revoluble chuck and a vacuum chamber, a tube, y

bellows and shaft providing communication betweensaid chuck and chamber,and vacuum operated meansto cut of! said communication;

2. In a 'device' of the characterdescribed, a

6o revoluble chuck and a vacuum chamber, a tube.

bellowsl and. shaft providing communication4 between said chuck andchamber, vacuum operated means to cut oi! said communication, `andmanually operable means to re-establish said communication. l

' CHARLES a. PE'raY.

20. whereupon the vacuum inthe chamber I 1 of the shoulders l' and 6'land prevent leakage.t 'The' ends of the hubs 29 are preferably rounded'f

